SUMMARY/ABSTRACT
Objective: Τo investigate the association of serum vitamin D
and nasal secretion antimicrobial peptides (AMPs) levels with the
severity of acute bronchiolitis.
Study design: We conducted a prospective single pediatric
tertiary care center cohort study of inpatients aged 0-18 months with a
first episode of acute bronchiolitis from November 1st2014 to April 30th 2017. Disease severity was
determined by the length of hospitalization and supplemental hospital
data. Qualitative measurements included serum 25(OH)D and nasal
secretion LL-37 and β-defensin-2 levels. Correlations were examined with
the Mann-Whitney and Kruskal-Wallis criteria for qualitative and the
correlation coefficient Spearman’s rho for quantitative factors.
Multiple linear and logarithmic regression were performed in order to
adjust for confounding factors.
Results: The study population consisted of 153 infants and
toddlers with mean age 3.6 months (SD: + 2.8). The median level of
serum 25(OH)D was 51.4 nmol/L (IQR: 29.7-72.2). No association was found
between serum 25(OH)D and AMPs nasal secretions levels. Serum 25(OH)D
and nasal secretion β-defensin-2 levels were not associated with the
severity of bronchiolitis. In contrast, LL-37 levels were inversely
associated with the length of hospitalization (rho = -0.340, p = 0.001)
and the need for medication use (p = 0.001) and this association
remained significant after adjustment for potential confounders.
Conclusion: A significant association between LL-37 nasal
secretions levels with the severity of acute bronchiolitis was found in
hospitalized infants and toddlers. The role of LL-37 in the pathogenesis
of bronchiolitis merits further investigation.